Electric-lighting system.



No. 783,509. PATEN'IED FEB. 28, 1905.

l A. G. DAVIS.

ELECTRIC LIGHTING SYSTEM.

APPLIOATION FILED MAR. 4, 1899.

SOUEC E 0 F CONSTA NTCl/RREIT.

MA1-[455555. I IPM/ENTER.

UNITED STATES Patented February 28, 1905.,

PATENT OEEICE.

ALBERT Cr. DAVIS, OE SCHENECTADY, NEWT YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEV YORK.

ELECTRIC-LIGHTING SYSTEM.

SPECIFICATION forming part of Letters Patent No. 783,509, dated February 28, 1905.

i Application filed March 4, 1899. Serial No. 707,702.

To mi] l/f/l/om il; mm1/y concern:

Be it known that I, ALBERT Cr. DAvIs, a citi- Zen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful .Improvements in Electric-Lighting Systems, of which the following is a specification.

It is now well known that certain substances known as {Nro-electrolytes act as conductors of electricity at high temperatures, but are insulating' at low temperatures, or, speaking more broadly, tend to have their resistance reduced as their temperature rises. It has been proposed to utilize such substances as light-giving bodies in electric lamps. It is necessary in such devices to in some way heat the light-giving material to a high temperature before it will take current, and various arrangements have been proposed for doing this, among which I may mention that invented by E.V WV. Rice, Jr., and described in his pending application, Serial No. 692,368. Iiled October I, 1898. A difiiculty which has arisen in such devices is that, though the efciencyis high, the lampis unstable. Its resistance variesinversely with its temperature, while its temperature varies more or less directly with the amount of current flowing through it. Therefore the greater the temperature the greater the conductivity and the greater the conductivity the greater the temperature, so that if the lamp once gets beyond a certain temperature it will take current indefinitely until it is destroyed. In a test it was found that a pyroelectrolyte connected in a constant-potential circuit heated up slowly and after reaching a proper conducting temperature instead of remaining thereat or thereabout rose rapidly in temperature and was fused and destroyed. It has been proposed to remedy this difhculty by placing regulating resistances in series with each lamp, placing the lamps as usual in multiple on constant-potential mains. This arrangement, however, involves a considerable waste of energy and is not entirely satisfactory.

In my improved system I utilize lamps of the general nature above described-"that is to say, lamps whose light-giving bodies are of a class the resistance of which is enormously high at starting. and decreases rapidly as the temperature rises-but I connect such lamps, preferably in series, on a constant-current circuit, either direct or alternating, as may be preferred. This entirely obviatcs the objection above noted and gives a more satisfactory regulation. If the temperature of the pyro-electrolyte from any local or other cause increases above the degree proper for normal conductance, the resistance decreases, but the current is constant, and hence the energy is correspondingly decreased and the temperature of the body is reduced to its normal degree. Again, if the temperature of the body decreases below the normal degree the resist- 05 vance increases, and as C2 is constant the energy is correspondingly increased and the temperature increases to its normal degree. The result, which has not hitherto been obtained, is a permanent self-regulating pyro- 7G electrolytic lamp; but as the resistance of the lamps when cold is so high it is impossible to insert them directly in the system in the manner in which arc-lamps are ordinarily inserted. I avoid this difhculty by placing in multiple with each lamp a resistance which is capable of being gradually short-circuited. This resistance may obviously be highly inductive, if desired. I also place on each lamp, in multiple with thelight-giving body, 8O a starting-coil or resistance, such as is shown in the application of E. WI. Rice, Jr., above referred to.

The accompanying drawings represent one g form which my invention may take. 35

Figure l is an elevation of the lamp, partly in section, with the cover removed. Fig. 2 is a section on the line 2 2 of Eig. l. Fig. 3 is a diagrammatic illustration of a system provided with three lamps in series.

A is the light-giving body, which may be composed, for example, of magnesia, marble, porcelain, or other substance possessing the qualities above set forth.

B is a spiral of high-resistance wire wrapped around or embedded in the body A.

C Cl are conductors which are connected to the terminals of the body A and the resistance or startingI wire I, respectively, and which l of supply is alternating, theresistance should further serve as mechanical supports for the 1iight-giving body.

i the impedai'lce.

I may, if preferred, incase the light-giving l 3 together by a screw M.

I have shown the mechanical structure of i the lamp as similar to that of the incandescent lamp of the well-known Edison type.

E is the shell which forms one terminal of the lamp, and Fi is the plug which forms the other terminal. A resistance R is arranged in multiple with the lamp and can be gradually short-circuited by a lever F in a manner to be more particularly explained hereinafter.

Referring now more particularly to Fig. 3, T is a source of constant current, such as a transformer of the so-called leakage or constant-current type, arranged to feed current of substantially constant volume to the circuit H. A number of lamps L Tj L are shown connected in series in this circuit, each of the lamps being shunted by the resistance B, controlled by the arm F. Further, each lamp is shunted by a lilm cut-out K, which comes into action in case for any reason the lamp may be destroyed. It is obvious that VI may substitute for this film cut-out any other similar device. 1n the drawings the lamps L? and Ilg are supposed to be burning, and the lamp L is supposed to be extinguished. It will be seen that the arm F rests on the resistance R in such a way that the lamp is entirely shortcircuited. Suppose now that it is wished to light the lamp L. The resistance-arm F is gradually moved in left-handed rotation tothe resistance R, thus cutting more and more resistance into the shunt, raising the potential across the terminals of the lamp, and forcing current to flow through the line wire B, Fig. l. This heats the light-giving body A,which gradually begins to take current before the resistance is entirely cut into the shunt, so that the heatingl resistance, which might be destroyed bythe full current, is not subjected thereto. By the time the arm F has reached the position shown in connectiouwith the lamp Tf, for example, the light-giving body will become of such low resistance that it will take ciu;i:ent-tsthe practical exclusion of the resistance B.

It is obvious that various other devices may be used Vfor furnishin, r initial heat to the lightgiving body A and that the resistance B need not necessarily be coiled around or embedded in the said body.

The inechanical construction necessary to carry out the method of operation above described is shown in detail in Figs. 1 and 2. The socket is supposed to be built of porcelain or other non-conducting material or to be lined with insulation. The resistance R is coiled around an insulating-support and is fastened in place by a clip M. IVhen the source have a core of soft iron I( in order to increase The socket itself is divided into two parts, as shown, which are fastened A metal strip M, bent twice around itself at right angles, is supported from the socket bythe bolt M". This forms a support for the mechanisni. The key (i drives a ratchet-wheel M, which in turn drives, through a pawl M5, a gearwheel MG. This gear-wheel drives, through the pinion M7, a second gea r-wheel M, which in turn, through the pinion M, drives the vane Mw. It is thus obvious that a lefthandcd rotationof thc plug' (i, Fig. 1, will be arrested by the action of the vane M10, so that it will take a certain definite time before any consideraliile rotation can be acconwlished. The shaft of the handle G drives the arm F, before alluded to, which travels over the resistance R.

The connections are as follows: The leading-in wires enter at the opening il) (shown in Figs. I and ii) and pass, respectively, to the terminals N N. The terminal N is connected to the metal support M, which in turn is connected, as shown, to the plug IC, which bears against the plug E of thel lamp-base. From the metal shell E', which forms the other terminal of the lamp, a wire leads to the terminal N2. VIt will be seen that a branch circuit is formed Yfrom the terminal N through more or less of the resistance R to the terminal N2, except when the arm F is in the position shown, which correspomls to the position shown in connection with the lamp L in Fig. 8.

This mechanism makes it necessary to turn on the lamp very slowly to allow time for the light-giving body A to attain a proper telnperat-ure before the resistance is open-circuited; but it makes it possible to turn oli the lamp very rapidly, as a right-handed rotation of the ratchet-wheel M'i is not opposed by the pawl MI. The pawl Mi is held in place by a spring M, as usual.

YIt will be obvious that my invention in its broader aspect is independent of the specilic mechanism here shown.

IVherever I have used in this specification or in the claims thereto attached the word resistance" I do not intend to limit myself to so-called dead7 or c"ohn1ic resistance, but aim to include inductivel resistance or any other equivalent suitable currcntlimiting means.

T'Iavi'ng thus described my invention, what 1 claim as new, and desire to secure by Letters Patent of the United States, is

l. Ifn an electric lamp, the combination of an illuminant which is non-conducting when cold and increases rapidly in conductivity when heated, means for heating thc same to conductance, and an automatic source of constant-current supply for Afurnishing current IOO IIS

to the illuminant, the automatic operation of which source enables the illuminant to operate with stability.

2. The combination with a source of substantially constant current, ot' a. plurality of lampsin series therewith, each lamp having an illuminating-body insulating at ordinary temperature, but conducting at higher' temperatures, the constant current serving to maintain the temperature and resistance of the body substantially constant, means for giving initial heat to each illuminating-body, and means for turning each lamp on and off without interrupting the circuit.

3. The combination with a source of substantially constant current, of a plurality of lamps in series therewith, and an adjustable resistance in multiple with each lamp, each lamp being composed of a body insulating at ordinary temperature, but conducting at higher temperature, said resistance being eapable of being gradually open-circuited in order to increase the potential around the terminals of the lamp, and means for giving initial heat to each lamp.

4. A lamp for electric circuits composed of a bod y, such as porcelain, magnesia, or similar material, with a resistance in multiple therewith, means for heating the body to conductance, and a handle or key for increasing said resistance as the lamp is turned on and decreasing the resistance as the lamp is turned off.

A lamp for electric circuits composed of a body, such as porcelain, magnesia, orsimilar material, with a resistance in multiple therewith, means for heating the body to conductance, a source of substantially constant current for said lamp, and a handle or lteyfor turning on the lamp by varying said resistance from Zero to iniinity substantially.

6. The combination with a source of constant current, of a pyro-electrolytic incandescing illuminant connected in series therewith, a heater for rendering the illuminant conducting, and a resistance in multiple with the illuminant, which is capable oi' being gradually short-circuited as the conductivity of the illuminant increases.

7. The combination with a source of substantiall y constant current, of lamps each having apvro-electrolytic illuminant and devoid ot' stead ying' resistance connected in series with said source, a resistance for initially heating said illuminant to lering it to conductivity, and a shunt-connected resistance which is capable of being' gradually increased in order to increase the potential around the lamp and force current through the initial heating resistance.

. 8. The combination with a source of constant current, ot a pyro-electrolytic incandescingilluminant connected in series therewith, a heating resistance in shunt to the illuminant for rendering the latter conducting, a second shunt around the illuminant, and a switch in the shunt.

9. The combination with a source oi' constant current, a pyro-electrolytic incandescing illuminant connected in series therewith, means for heating the illuminant to a state of conductance, a shunt around the illuminant, and variable resistance in the shunt whereby current is admitted gradually to the lamp.

10. The combination with a source ot' constant current, of a pyro-electrolytic incandescing illuminant connected in series therewith, a heating resistance for theilluminant in shunt thereto, and variable resistance in shunt to the illuminant, which is cut in to gradually increase the current flowing through the heating resistance, which latter thereby heats the illuminant to conductance, so that the illuminant takes current before the t'ull current is permitted to flow through the heating resist.- ance.

11. In an electric lamp, the combination with a pyro-electrolytic incandescing illuminant, of means for heating the same to conductance, means for maintaining a constant flow of current through the illuminant irrespective of the resistance of the illuminant, a resistancein parallel with the illuminant, and means for cutting the resistance in slowly to turn on the lamp, and for cutting it out rapidly to turn oli the` lamp.

l2. A lamp for electric circuits composed of a body, such as porcelain, magnesia, or similar material, with a resistance in multiple therewith, and a handle or key foi-varying said resistance, from Zero to infinity substantially and means for preventing a rapid motion of said handle in one direction.

13. A lamp for electric circuits composed oli a body, such as porcelain. magnesia, or similar material, with a resistance in multiple therewith, and a handle or key for varying said resistance, and means for preventing a rapid lnotion of said handle in one direction.

Vln witness whereof l have hereunto set my hand this lst day of March, 1899.

ALBERT DAVIS. itfitiiesses:

BENJAMIN B. HULL, MABEL E. JAcousoN.

IOO 

